Mutagenicity tests with gallic and tannic acid in the Salmonella/mammalian microsome assay

Gallic acid, tannic acid mixture and a purified fraction of tannic acid were evaluated for possible mutagenic activity in three strains of Salmonella typhimurium, TA98, TA100, and TA1535. These chemicals were not mutagenic either before or after activation with rat and woodchuck microsomal and cytosolic enzymes. However, tannic acid mixture and tannic acid fraction both gave a significantly (p = 0.05) dose-related reduction in the number of the revertant colonies, compared to the normal spontaneous revertants with no apparent toxic effects in the background lawn. With an agar diffusion assay, the chemicals exhibited toxic effects at 5000 micrograms/disc.     

The control effect of fungicide pyraclostrobin against freckle disease of banana and its residue dynamics under field conditions

ABSTRACT

Fungicide pyraclostrobin has been widely employed to control plant diseases by inhibiting the mitochondrial respiration of pathogenic fungi. Due to its broad spectrum, the extensive use of pyraclorstrobin was reported to cause emerging resistance on crops. Here, we evaluated the control effect of 250 g L^?1 of pyrachlostrobin suspension concentrate (SC) against freckle disease (caused by Phyllosticta spp) on banana. Meanwhile, the dissipation and residue dynamics of pyraclostrobin in banana and soil under field conditions were determined by high performance liquid chromatography (HPLC) with DAD detection in different locations. The analytical method was validated using spiked samples at three levels, which indicated the recoveries ranged from 92.0% to 99.0% with relative standard deviations (RSDs) below 5%, providing a sensitive, precise and reliable method to monitor pyraclostrobin in banana fruit and soil. The dissipation of pyraclostrobine followed the first-order kinetics and its half-lives were 5.25 to 9.90 days. In addition, the terminal residues of pyraclostrobin in banana, banana sarcocarp and soil were below the maximum residue limit (MRL) (0.02 mg kg^?1) after a pre-harvest interval (PHI) of 42 days, which suggesting that the use of pyraclostrobin at recommended dosages was safe to banana and the environment. In summary, we demonstrated the integrated evaluation on the disease control capacity of pyraclostrobin and its environmental behavior on banana, aiming to provide solid and basic data for the safe use of fungicide pyraclostrobin.     

Evaluation of chlordimeform and degradation products for mutagenic and DNA‐damaging activity in salmonella typhimurium and escherichia coli

Abstract

The mutagenic activity of chlordimeform and two of its breakdown products, 4‐chloro‐o‐toludine and 4‐chloro‐N‐formyl‐o‐toluidine were determined with five histidine dependent strains of Salmonella typhimurium (TA1535, TA1537, TA1538, TA98, TA100) and five tryptophan dependent strains of E. coli WP₂. (WP₂, WP₂uvrA, WP67, CM611, CM571) with and without rat liver microsomal enzymes. 4‐chloro‐o‐toluidine increased the number of the reversions of the S. typhimurium strain TA1535 more than two fold over spontaneous at the concentration of 400 μg/plate.

The results of the DNA repair tests in the Salmonella TA1538/TA1978 and E. coli multirepair deficient systems showed that both breakdown products were active in inducing damage not repaired in at least one repair deficient strain while chlordimeform itself was inactive.     

Technological disaster factors

Major Hazard Installations (MHIs) deal with the hazardous substances which exceed the threshold quantity. Although MHIs are safe organizations, they cannot fail due to a single error. However, due to their high complexity, the designer and the operator make errors during the design, and operation of the plants. Consequently, the technical, operational and organizational errors may lead to a major accident. The world has seen many incidents due to the operation of the MHIs. Malaysia has experienced several technological disasters. Four investigation reports have been reviewed in detail. This paper reviews the causes of the technological disasters in general. This paper also summarizes the causes of the technological disasters in Malaysia. Finally the paper rearranges the technological disaster causes and errors.     

Spatial�Ctemporal assessment and redesign of groundwater quality monitoring network: a case study

Assessment of groundwater quality monitoring networks requires methods to determine the potential efficiency and cost-effectiveness of the current monitoring programs. To this end, the concept of entropy has been considered as a promising method in previous studies since it quantitatively measures the information produced by a network. In this study, the measure of transinformation in the discrete entropy theory and the transinformation?Cdistance (T?CD) curves, which are used frequently by other researchers, are used to quantify the efficiency of a monitoring network. This paper introduces a new approach to decrease dispersion in results by performing cluster analysis that uses fuzzy equivalence relations. As a result, the sampling (temporal) frequency determination method also recommends the future sampling frequencies for each location based on certain criteria such as direction, magnitude, correlation with neighboring stations, and uncertainty of the concentration trend derived from representative historical concentration data. The proposed methodology is applied to groundwater resources in the Tehran?CKaradj aquifer, Tehran, Iran.     

Spatio-temporal assessment of land use dynamics and urbanization: linking with environmental aspects and DPSIR framework approach

Environmental Science and Pollution Research - Urbanization is the main force of the global environmental as well as land use land cover changes (LULC). Urbanization is caused by prompt increase in...     

Potential of 2,4-dichlorophenoxyacetic acid conjugates as promutagens in the Salmonella/microsome mutagenicity test

Hepatic S9 preparations from Aroclor 1254 induced rats and 3-methylcholanthrene induced woodchucks were used to investigate, in vitro, the mutagenic potential of five amino acid conjugates of 2,4-Dichlorophenoxyacetic acid (alanine, aspartic acid, leucine, methionine and tryptophan). Five strains of Salmonella typhimurium (TA97, TA98, TA100, TA1535, TA1538) were utilized for this purpose. Dose-response effects producing a two-fold increase of revertants over spontaneous levels were not observed with either S9 preparation indicating that the amino acid conjugates are not promutagens in these assays.     

Urban Flood Problems in Dhaka,Bangladesh: Slum Residents’ Choices for Relocation to Flood-Free Areas

This article applies a stated preference choice model to assess trade-offs that residents of two squatter settlements in Dhaka, Bangladesh might consider if they were given choices for relocation to flood-free areas. The respondents were asked to choose repeatedly from a set of choice cards, which displayed different configurations of financial incentives for relocation, such as free or inexpensive land, loans or nonrepayable grants, and provisions for temporary or permanent employment opportunities. The survey results indicated that despite extensive experience with flood problems, many residents of Mirpur and Vasantek found that certain configurations of economic incentives were not attractive enough for them to relocate to flood-free areas. At the same time, they would prefer a reduction in the risk of flooding at their current location. The economic incentives that would best assist in increasing voluntary relocation of residents from their current locations included free land, nonrepayable grants (Taka 20,000), and long-term employment opportunities. Further, differences in geographic location (i.e., Mirpur vs. Vasantek), income levels, and membership in neighborhood communities were linked with the tendency of residents to stay at their current location.     

Scenarios for investigating the future of Canada’s oceans and marine fisheries under environmental and socioeconomic change

Regional Environmental Change - There is a critical need to develop effective strategies for the long-term sustainability of Canada’s oceans. However, this is challenged by uncertainty over...